A thiazole compound represented by the formula (3):
wherein X1 represents a hydrogen atom or a halogen atom, a representative of which is 2-chloro-5-(aminomethyl)thiazole, is a compound useful as an intermediate for medicine and agrochemicals (see, for example, JP 7-14916 B). For producing it, several processes have been known. For example, there are (a) a process in which a compound represented by the formula (1):
wherein X1 is as defined above, and X2 represents a halogen atom, is reacted with hexamethylenetetramine, followed by hydrolysis (see, for example JP 4-234864 A and JP 4-21674 A), (b) a process in which a compound represented by the above formula (1) is reacted with potassium phthalimide, followed by hydrazine degradation (see, for example JP 4-234864 A), (c) a process in which a compound represented by the above formula (1) is reacted with formamide, followed by hydrolysis (see, for example, JP 5-286936 A), and (d) process in which a compound represented by the above formula (1) is reacted with ammonia (see, for example, JP 4-234864 A and JP 2000-143648 A).
In all of the aforementioned processes (a) to (c), yields of the objective thiazole compound represented by the formula (3) are low, and those processes are unsatisfied from the industrial viewpoint. Although the process (d) is advantageous over the processes (a) to (c) in that more inexpensive ammonia is used, further improvement has been demanded because a considerable amount of a compound represented by the formula (4):
wherein X1 is as defined above, is formed as a byproduct even when ammonia is used in the amount of 20 moles or more per mole of the compound represented by the above formula (1), and a yield of the objective thiazole compound represented by the formula (3) therefore is low.